Article

OBJECTIVE: To compare the ankle muscle strength and torque-angle relationship
between individuals with Parkinson's disease (PD) and participants without
impairments. DESIGN:
Cross-sectional, exploratory study. SETTING: Motor control
laboratory in a university. PARTICIPANTS: Convenience sample of
community-dwelling individuals with PD (n=59) recruited from a PD self-help group
and age-matched participants without impairments (n=37) recruited from community
older adult centers. MAIN OUTCOME MEASURE: Peak
torque and angle-torque profile during concentric and eccentric contraction of
ankle dorsiflexors and plantarflexors at 2 different angular speeds (45 and 90
degrees /s). RESULTS:
The PD group displayed lower muscle peak torque values than
participants without impairments in all test conditions. Generally, concentric
strength was more compromised, with a greater between-group difference (Cohen d=1.29-1.60) than eccentric strength (Cohen d=.81-1.37). Significant group by
angular speed interaction was observed in ankle plantarflexion concentric peak
torque (P<.001), indicating that muscle weakness was more pronounced when the
angular speed was increased. The group by joint angle interaction in concentric
contraction of ankle plantarflexors at 90 degrees /s was also significant
(P<.001), revealing that the between-group difference in torque values became
increasingly more pronounced when the joint was moving toward the end range of
the ankle plantarflexion. This exaggerated ankle plantarflexor muscle weakness at
the end range was significantly correlated with clinical balance measures (P<.05). CONCLUSIONS: Muscle weakness in PD is influenced by contraction type,
angular speed, and joint range. Exaggerated weakness is found in concentric
contraction of ankle plantarflexors, particularly when the angular speed is high
and the muscle is in shortened lengths.
CI - Copyright (c) 2012 American Congress of Rehabilitation Medicine. Published by
Elsevier Inc. All rights reserved.

Langue : ANGLAIS